1. Field of the Invention
This invention relates generally to sensor devices, and more particularly to a sensor device and method for monitoring physical rehabilitation exercises and the like, and alerting the user if the exercises are being performed incorrectly.
2. Description of Related Art
There are various devices in the prior art that teach sensor devices for measuring pressure placed upon a user's foot for the purposes of assisting in rehabilitation of a user's leg following an injury.
Knotts et al., U.S. Pat. No. 5,107,854, teaches a slipper that includes a fluid chamber that enables weight sensing by a load monitor. When not enough weight is applied, or when too much weight is applied, a beeping sound is emitted to guide the patient in rehabilitating an injured leg.
Huberti, U.S. Pat. No. 5,042,504, teaches an insertable sole that includes plates having force sensors for determining a load placed upon the sole by a user. An amplifier and AC/DC converter generate a force signal that is received by a processor for generating audible and visual feedback via a piezo-beeper and display screen.
Gray, U.S. Pat. No. 5,269,081, teaches a force monitoring shoe that includes a spring, a sensor for sensing force applied to the spring, and a feedback mechanism that may include a beeper, flashing LEDs, a shocking element, vibrational (tactile) feedback.
Gray, U.S. Pat. No. 5,357,696, teaches a force monitoring shoe similar to the '081 patent, utilizing a force monitoring device to measure force exerted on the shoe, warn the patient (e.g., a beeper) if predetermined force levels are exceeded, and collect the accumulated data in a data gathering device. The pressure sensor may be a resistive sensor pad, and the patient alerting elements may include a wireless transmitter that transmits a signal to a separate unit that vibrates in response to exceeding recommended forces. The data gathering device may be a recorder, or a receiver in a doctor's office.
Schmidt et al., U.S. Pat. No. 5,619,186, teaches a rehabilitation device that measures force exerted on a sensor in a shoe for the purposes of guiding a patient in placing the correct amount of weight on an injured leg.
Schmidt et al., U.S. Pat. No. 5,408,873, teaches a similar foot force sensor that includes a special insole made of layers of relatively thin, planar, flexible dielectric material. Electrical contacts are interposed between the layers for sensing force.
Avni et al, U.S. Pat. No. 6,273,863, teaches a rehabilitation device that measures force exerted on a sensor in a shoe for the purposes of guiding a patient in placing the correct amount of weight on an injured leg.
Fullen et al., U.S. Pat. No. 5,323,650, teaches a rehabilitation device that includes a force sensor array adapted to be positioned in a shoe, a cable for connecting the force sensor array with an electronic circuit module that includes a CPU, RAM, ROM, and scanning circuitry for continuously electronically scanning the sensor array to determine instant force sensed by the sensors.
Gray, U.S. Pat. No. 6,122,846, teaches a force monitoring shoe similar to the other Gray patents described above. The shoe includes two semi-rigid plates, with a force sensor positioned therebetween. The force signals generated are transmitted via wireless to a reporting device that is separate from the shoe. The reporting device not only displays the readings, it may also be used to transmit the data to a remote computer for storage and analysis.
Beebe et al., U.S. Pat. No. 7,277,021, teaches a device for determining the wear of a sole of a shoe, to determine when the shoe is worn out and needs to be replaced. A control circuit connectable to first and second sensors compares the difference between the first and second signals to a threshold and generates an alert signal in response to the difference between the first and second signal meeting the threshold, thereby indicating that the shoe needs to be replaced, at which point an LED is illuminated.
There are various sensor devices that include accelerometers for various purposes. For example, Hirsch et al., U.S. Pat. No. 6,578,291, teaches a shoe having a built-in electronic wear indicator device that includes an accelerometer for measuring foot movement.
Damen et al., U.S. Pat. No. 6,356,856, teaches a system built into a shoe or measuring the speed of a person while running or walking. An acceleration sensor measures the acceleration in the forward direction and provides an acceleration signal which is amplified and subsequently sampled by analog to digital converter. The digital signal is processed by a microprocessor which executes an algorithm that determines the stride length and the stride duration from the digitized acceleration signal and calculates the speed and the distance traversed. The information thus obtained is transmitted by an RF transceiver to a watch or other device which includes a display which can be viewed by the runner or walker. The speed and distance traversed is displayed on the display, along with other useful information, such as average speed, maximum speed, total distance traversed, calories expended, and heart beat. Similar shoes are also shown in Huang, U.S. Pat. No. 5,875,571, Huang, U.S. Pat. No. 5,815,954, Hutchings, U.S. Pat. No. 5,724,265, and Huang, U.S. Pat. No. 5,661,916.
Cherdak, U.S. Pat. No. 5,452,269, teaches an athletic shoe which includes a timing device for measuring the amount of time the athletic shoe is off the ground and in air. The athletic shoe includes a notification device which can be operatively coupled to the timing device for notifying a wearer of the amount of time the athletic shoe is off the ground and in the air.
Wood, U.S. Pat. No. 5,373,651, teaches footwear adapted to measure the number and the force of steps that have been taken by the user during a predetermined interval. The wearer can subsequently transfer the step information into a computer for further analysis via an inductively coupled data link between the footwear and the computer.
Adams et al., U.S. 2007/0049853, teaches a compression device for a limb of a patient for applying a predetermined amount of pressure to the limb, and for reporting the pressure actually applied to the limb via an external reporting device. The compression device includes an inflatable sleeve arranged to surround the limb, and a conduit attached to the sleeve arranged to deliver fluid to the sleeve for providing the pressure. A control system controls fluid flow in the device and a memory arranged to store gathered data relating to use of the device.
The above-described references are hereby incorporated by reference in full.